Project Summary Several human pathologies lead to retinal ganglion cell (RGC) degeneration and irreversible vision loss. Stem cell-based cell replacement therapy offers promising novel approaches for vision restoration. However, there are many issues to overcome before these therapies can be clinically trialled: The current methods to differentiate embryonic stem cells (ESCs) into retinal fates yield modest numbers of RGCs, and previous reports have suggested that only a small fraction of RGCs can integrate with a host retina upon transplantation. The main goals of the present proposal are: (1) to improve the current protocols to efficiently differentiate ESCs into RGC fates at the optimal age for transplantation, and (2) to identify possible barriers to cell engraftment. 1) To generate high yields of ESC-derived RGCs: Our lab and others have implemented methods to differentiate embryonic stem cells into bona-fide retinal progenitors. We will develop the current protocols to increase the production of RGCs by systematically testing an array signaling cues and miRNA regulators known to be involved in RGC differentiation during normal development. By using a variety of approaches including RNA-sequencing and electrophysiology, we will characterize the ESC-derived RGCs. We will label, purify and transplant RGCs from an array of different ages to pinpoint the optimal developmental stage to become donor cells for transplantation. 2) To analyze integration potential of ESC-derived RGCs following transplantation: We will use state- of-the-art imaging technologies to follow individual ESC-derived RGCs after transplantation in living rodents to accurately measure survival, migration and integration with the host. We will employ murine models of RGC degeneration to assay the role of the environment in RGC engraftment potential.